The extraction of beryllium by triisooctylamine is measured over the pH range from 1 to 10, in the presence of malonic, maleic, succinic, phthalic, and salicylic acids. Values are obtained for the stability constants of the various metal-acid complexes by potentiometric titration. The degree of extraction is dependent on the abundance of the anionic complex present in the aqueous phase and this is in turn dependent on the strength of the corresponding acid and the stability of the complex. (auth).

Details are given of an apparatus used to dissolve irradiated ceramic, metallic, and carbide fuel specimens, to dilute the dissolver solutions accurate to a known volume, and to take aliquots with a specially adapted automatic burette. Procedures for its use are given.

Methods are described for the determination of traces of Be, Th, and U in concentrated sulfuric-phosphoric acid mixtures. When the Be concentration is sufficiently high, the chrome azurol S spectrophotometric method may be applied directly, and a small correction made for phosphate interference. At lower concentrations Be should be first separated by an acetylacetone extraction. Th must be separated from sulfate and phosphate before the thoronol spectrophotometric method can be used. This is achieved by precipitating Th as the fluoride, using Y carrier. U may be determined spectrophotometrically with arsonazo after separating Be, Th, suIfate, phosphate, and other impurities by anion-exchange from hydrochloric acid solution. In an alternative procedure, U is reduced to the tetravalent state and precipitated with Th as the fluoride, again using Y carrier. The determination is then completed by a-c polarography.

The dissolution of dense beryllia was studied in a variety of reagents. The dissolution rates were too slow to be of practical importance except those for hydrofluoric acid, sulfuric acid, and mixtures of sulfuric and phosphoric acids. The reaction with hydrofluoric acid was studied in more detail in an attempt to throw some light on the dissolution process. The initial dissolution rate appeared to be proportional to the square of the acid concentration between 0 and 20M. An apparent activation energy of 12 Kcal/mole BeO was obtained from the temperature coefficient of the dissolution.

The 25% Cr, 20% Ni type stainless steel has been proposed for use in the Australian High Temperature Gas Cooled Reactor in core structures, and in hot gas ducting. Thus a knowledge of the compatibility of this steel with high pressure carbon dioxide was required. Rates and mechanisms of corrosion were investigated for machined, vapour blasted, and etched pretreated samples of this steel, exposed to carbon dioxide up to 3,000 hours in the temperature range 650 degrees C at gas pressures from 3 p.s.i.g. to 280 p.s.i.g. Oxide film flaking as apparent at all temperatures investigated but was only severe for pre-ground samples at 710 degrees C and above, and for pre-vapour blasted samples at 760 degrees C and above. However, severe intergranular penetration was observed in pre-etched samples on exposure to carbon dioxide at 650 degrees C and above. Pressure of the gas appeared to have no systematic effect on the corrosion rate, at least in the temperature range investigated. The maximum useful temperature for which the steel could be used would be limited by the amount of oxide flaking permissible. In reactor gas circuits where a small amount of scale flaking could be tolerated, the steel is satisfactory …

A method is described for the computation of the energy dependence of the neutron flux and slowing down density in a bare reactor to form the basis of a 7090 Fortran computer program for survey studies of power reactors. Allowance is made for resonance absorption and resonance fission, neutron thermalisation, fast neutron reactions including (n, 2n) and (n, n), and anisotropic elastic scattering.

A method is described whereby the density of a single crystal of beryllium oxide can be measured by suspending it in a dense liquid. The method is being used to measure radiation-induced changes in density and is sensitive to 1 part in 10(5). The absolute accuracy has not been established owing the lack of a suitable standard.

Kalberer and Rutschmann (Helv, Chim, Act, 44 : 1956, 1961) described a method of estimating quantitatively C-14 compounds on a paper carrier, for example chromatograms. The sample is combusted in oxygen, the C14O2 produced being absorbed in ethanolamine solution and counted by liquid scintillation techniques. However, errors occur where there are deviations from their experimental conditions, such as in counting equipment or weight combusted, owing to differing concentrations of dissolved oxygen in counting solutions. Those errors can be eliminated by scrubbing the ethanolamine absorption solutions with nitrogen before they are mixed with the liquid scintillant. Furthermore, by this additional step, the range of weights combusted can be extended form 130 - 200 mg to 0-200 mg.

Order-of-magnitude estimates of the fast neutron elastic scattering rate have been obtained to supplement metallurgical studies of the fast neutron damage in some small beryllium oxide-based dispersed fuel specimens. The elastic scattering rate for neutrons with energies above 0.1 MeV is shown to be of the the order of 30 per cent of the fission neutron release rate in the specimens, owing to significant fast neutron leakage. The ratio of the Be (n,2n) reaction rate to the fission neutron release rate in the specimens is of the order of only 6 per cent of its value for an infinite medium of beryllium oxide.